Technical Field
The invention relates to a packaging technique, and more particularly, to a package structure and a bonding method of a package structure.
Description of Related Art
With the evolution of semiconductor packaging technology, different package types have been developed for semiconductor devices, such as wire bonding, flip chip or hybrid (i.e., flip chip together with wire bonding) packaging techniques. However, the above bonding techniques with use of a solder balls may encounter problems like bonding surface separation due to long-term fatigue, reliability issue caused by the defective solder during the manufacturing process, and relatively high resistance on contact points.
Currently, a chip packaging technique using a copper structure for bonding has been developed to conduct bonding between chip and package carrier in a press-fitting manner. Nonetheless, implementation conditions for achieving the existing copper requires the temperature of 300° C. to 450° C. with the pressure up to 300 MPa, and an annealing process after bonding. In addition, because the surface of the copper structure needs to be well cleaned for obtaining a flat surface through a chemical polishing process (CMP) before bonding, the manufacturing process is complicated so manufacturing cost cannot be reduced. Moreover, the underfill used after bonding for reducing the size of the package structure and refining the contact points may not be able to reliably cover the contact points each time such that quality and reliability for bonding may be reduced accordingly.